Fatty Acid Synthesis

Fatty acids are taken up by cells, where they may serve as precursors in the sythesis of other compounds

as fuels for energy production, and as substrates for ketone body sythesis

Ketones bodies may be exported to other tissues where they can be used for

energy production

Fats are an important source of dietary calories. Typically ___% of calories in the American diet are from fat.

30-40

Fat is the major form of energy storage. In a typical individual the fuel reserves are distributed as follows:

fat: 100,000 kcal

protein: 25,000 kcal

carbohydrate: 650 kcal

Fatty acids are intermediates in the sythesis of other important compounds. Examples include:

phospholipids (in membranes), Eicosanoids, including prostaglandins and leucotrienes, which play a role in physiological regulation

Some diseases involve disturbances in fatty acid metabolism. These include:

diabetes mellitus, specific disorders of fatty acid oxidation, such as Sudden Infant Death Syndrome and Reye Syndrome, which might be related to a deficiency of medium chain acyl CoA dehydrogenase, an important enzyme of fatty acid oxidation

Here are the major metabolic sources of acetyl CoA and some of the pathways for which it serves as a substrate

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Acetyl CoA is at the center of lipid metabolism. It is produced from:

Fatty acids, glucose (through pyruvate), Amino acids, Ketone bodies

Acetyl CoA can be converted to fatty acids, which in turn give rise to:

triglycerides, phospholipids, eicosanoids, ketone bodies

Acetyl CoA is the precursor of cholesterol, which can be converted to:

CoA is a commonly used carrier for activated acyl groups (acetyl, fatty acyl and others). The thioester bond which links the acyl group to CoA has a large negative standard free energy of hydrolysis (-7.5kcal/mole). This qualifies it as a high energy bond, and explains why an acyl group attached to CoA in this manner is considered to be activated.